1. Field of the Invention
The present invention relates to a Cu wiring forming method of forming Cu wiring that is to be arranged in contact with tungsten wiring, by filling Cu in a recess such as a trench or hole formed in a substrate, a film forming system and a storage medium storing a program for controlling it.
2. Description of the Related Art
In manufacture of a semiconductor device, various processing such as film forming processing and etching processing on a semiconductor wafer are repeatedly performed to manufacture a desired device, and speed-up of the semiconductor device, shrinking of a wiring dimension, and denser integration are increasingly demanded. Since there is a need to reduce signal delay in order to increase the operating speed of the device, and also from the viewpoint of energy saving of the device, Cu wiring having an interlayer dielectric film lower in resistance and dielectric constant than aluminum (Al) and tungsten (W), is widely used as a wiring material.
As the Cu wiring forming method, there is a conventionally known method in which a barrier film made of tantalum metal (Ta), titanium (Ti), a tantalum nitride (TaN) film, a titanium nitride (TiN) film or the like is formed on the entire interlayer dielectric film formed with a trench or a hole by plasma sputtering being PVD in order to prevent diffusion of Cu, a Cu seed film is formed on the barrier film similarly by plasma sputtering, and Cu plating is further performed thereon to completely fill the trench or the hole.
However, with the scaling dimension of the semiconductor device in recent years, it becomes difficult to fill Cu into the recess such as the fine trench or hole without causing voids by the conventional filling technology using plating after the barrier film and the Cu seed film are formed by PVD. Hence, a technology of forming a ruthenium (Ru) film as a liner film by CVD and forming a Cu film using dry fill by iPVD thereon has been developed (for example, Patent Document 1).
[Patent Document 1] Japanese Laid-open Patent Publication No. 2012-169590